In slicing foodstuffs a slicing machine having a slicing blade is used to cut slices from a log of cheese, meat, or meat product at a constant repetition rate. The cut slices fall onto what is known as a jump conveyor which, typically, moves forwards at a slow speed to provide a shingle of slices and then, after a predetermined number of slices or a predetermined weight of foodstuff has been cut, accelerates and travels briefly at high speed. Recent jump conveyors have been arranged to have a fast jump operation so that the jump operation is carried out entirely in an interval between the cutting of consecutive slices. Typically a jump conveyor is followed by another conveyor which forms part of a downstream packing line. The following conveyor generally runs at a higher speed than the jump conveyor so that the separation between the groups of slices is increased as they are transferred onto the following conveyor.
A slicing machine capable of high speed operation can cut as many slices as around 1750 per minute. It is usually the jump conveyor which provides the limitation on the slicing speed because as the slicing speed of the slicer increases so the time interval between consecutive slices gets shorter and this means that the jump conveyor has less time to separate one group from another.
Our U.S. Pat. No. 5,125,303, the disclosure in which is hereby incorporated by reference, describes a combined jump conveyor and slicing machine capable of high speed operation. The arrangement described provides a jump conveyor formed of two separate conveyors. When the slicing machine is required to form shingled groups of slices then the first conveyor moves forwards slowly such that the slices are formed into a shingled group on it. Since the first conveyor is generally shorter than a group of shingled slices, during shingling both the first and second conveyor move at the same slow forwards speed and, in this way, accommodate a long shingle of slices. Once slicing of the group has been completed both the first and second conveyors are moved at a high speed in the interval between the slicing of two consecutive slices to create a gap between successive groups. As soon as the group has left the first conveyor the first conveyor can again be slowed down ready to receive the first slice of the following group. Equally, as soon as the end of the group has passed onto the second conveyor the second conveyor can carry on at high speed or can be decelerated so that the sliced group of product is transferred to a downstream packaging line at the line speed of that product. When the jump conveyor is preparing shingled groups of slices the second conveyor slows down to the shingling speed as soon as it has transferred the preceding group so that it can again cooperate with the first conveyor to hold the next shingled group as it is cut. Both conveyors of the jump conveyor have independent drive and control means to drive the two conveyors at the same speed or at different speeds. The independent drive and control means of the first conveyor also enable it to be driven at high speed in the reverse direction away from the second conveyor to reject slices cut by the slicing blade, for example when the cut face of the log is not uniform.
There has been a problem detected with the combined jump conveyor and slicing machine of U.S. Pat. No. 5,125,303 in that where particular foodstuffs, for example American Bacon, are to be sliced by the slicing machine and jump conveyor, the first few slices of a shingled group of slices are prone to sliding as they land on the first conveyor. This is generally due to the thinness of cut and dryness also sometimes the bacon is too cold and icy due to inconsistent freezing/conditioning of the product of the foodstuff. The last slices can also fall back from the acceleration of the jump function. As a result the shingled group of slices are presented in a finished pack having an uneven overlap between adjacent slices of the shingled group.
It is therefore an object of the present invention to provide an improved combined jump conveyor and slicing machine capable of providing a shingled group of slices having a constant shingle overlap in order to improve shingle pack presentation, irrespective of the foodstuff being cut.
According to a first aspect of this invention in an apparatus comprising a jump conveyor and a slicing machine for providing groups of shingled slices, said slicing machine including a slicing blade, said jump conveyor including a first slice receiving section and a second slice receiving section, said first slice receiving section having a proximal end adjacent to the slicing machine, a distal end, and a first slice receiving surface, said second slice receiving section having a second slice receiving surface, said jump conveyor being located adjacent said slicing blade so that said first slice receiving surface receives slices cut by said slicing blade directly, the improvement wherein said first slice receiving section is articulated about its distal end with respect to said second slice receiving section to be articulatingly movable relative to said second slice receiving section to vary the angular orientation of said first slice receiving surface.
With the arrangement in accordance with this invention the first slice receiving section of the jump conveyor can be articulated with respect to the second slice receiving section to present a less acute angle for the first slice of a shingled group of slices to land on. By presenting a less acute angle to the first slice a greater contact area between the first slice and the first slice receiving surface may be created upon initial contact between the first slice and the jump conveyor, thus reducing the possibility of the first slice slipping as it makes contact, and as the jump conveyor moves forward at a shingling speed. The angular orientation of the first slice receiving surface may be moved to a lowermost position which corresponds to a position in which the first slice receiving surface receives a first slice of the group of shingled slices cut by the slicing blade. Accordingly, an optimal orientation of the first slice receiving surface is created to prevent the occurrence of slipping of the first slice on the jump conveyor. Since the slices are being cut to form a shingled group of slices, the second slice of a group of shingled slices will partially overlap the first slice and so the angular orientation of the first slice receiving surface for receiving the second slice of the shingled group may be adjusted to ensure that the slices form the correct shingle overlap and that the slices do not slip on the jump conveyor. The angular orientation of the first slice receiving surface may be varied so that as subsequent slices of the shingled group are cut and land on the first slice receiving surface, the first slice receiving surface is articulatingly moved to an uppermost position corresponding to a position in which the first slice receiving surface receives a final slice of the group of shingled slices. A rate of change of angular orientation of the first slice receiving surface may be varied according to which slice of the group of shingled slices is cut by said slicing blade.
In a first preferred embodiment, the jump conveyor comprises a first conveyor including the first slice receiving section and the second slice receiving section, and a second conveyor, the second conveyor being located downstream of the first conveyor and having a third slice receiving surface. The first conveyor and the second conveyor may each have the form of a multi-element strip conveyor, the first conveyor having a proximal end located adjacent the slicing blade and a distal end located furthest from the proximal end, the second conveyor having a proximal end located adjacent the distal end of the first conveyor, the distal end of the first conveyor having a reduced diameter adjacent the proximal end of the second conveyor to facilitate smooth transfer of slices from the first conveyor to the second conveyor.
Preferably, both the first and second conveyors are driven by servomotors which have a very high torque and are controllable to a high degree. In this way the motors, and hence the conveyors, can be both accelerated and decelerated rapidly in the interval between the cutting of two consecutive slices by the slicing machine. Preferably, the first and second conveyors in the operation of the slicing machine are all under the control of a program controller, or a program logic controller, so that the timing of the speed changes in the first and second conveyor are directly coupled to the operation and slice cutting of the slicing machine. Further preferably, the first conveyor and the second conveyor each have an independent drive means controlled independently by a control means to drive and control the conveying speed of the first conveyor and the conveying speed of the second conveyor, respectively. The driving control means may drive both the first and second conveyors at a shingling speed or at a jump speed, or may drive the first conveyor at a shingling speed whilst the second conveyor is driven at a jump speed. The independent driving control means may further enable operation of the first conveyor at a high speed in the reverse direction away from the second conveyor.
Alternatively, in a second preferred embodiment, the jump conveyor comprises a first conveyor comprising the first slice receiving section, and a second conveyor comprising the second slice receiving section. The first conveyor and the second conveyor may each have the form of a multi-element strip conveyor, the first conveyor having a proximal end located adjacent the slicing blade and a distal end located farthest from the proximal end, the second conveyor having a proximal end located adjacent the distal end of the first conveyor, the distal end of the first conveyor having a reduced diameter adjacent the proximal end of the second conveyor to facilitate smooth transfer of slices from the first conveyor to the second conveyor. As in the first preferred embodiment, the first conveyor and the second conveyor may each have an independent drive means controlled independently by a control means to drive and control the conveying speed of the first conveyor and the conveying speed of the second conveyor, respectively.
According to a second aspect of this invention there is provided a method for producing the shingled group of slices using the apparatus according to the first aspect, the method comprising the steps of articulating the first slice receiving section of said jump conveyor downwards to a lowermost position relative to the second slice receiving section, driving the jump conveyor at a shingling speed, cutting a first slice of a shingled group of slices from a log of product using the slicing blade, the first slice landing on the first slice receiving surface, progressively articulating the first slice receiving section upwardly towards an uppermost position relative to the second slice receiving section as subsequent slices of the shingled group of slices are cut from the log and land on the first slice receiving section to form the shingled group of slices having a predetermined shingle overlap, accelerating the jump conveyor to a jump speed to discharge the shingled group of slices therefrom, decelerating the jump conveyor to the shingling speed whilst articulating the first slice receiving section downwardly to the lowermost position relative to the second slice receiving section, and cutting a first slice of a second shingled group of slices from the log of the product using the slicing blade, the first slice landing on the first slice receiving surface.